Apple gushed out a wave of new features in iOS 5, the latest version of its mobile OS landing on selected iPad, iPhone and iPod touch devices this autumn. It contained many features we'd been expecting, and most users will be very happy with the new native apps -- but it will leave a number of developers wondering if anyone will use their software any more.

Here are just a few of the possible casualties of Apple's latest update.

Instapaper

On the surface, Instapaper has been made obsolete by the new 'Reading List' in the Safari browser, which allows users to sync and store online articles for later reading. Developer Marco Arment's initial reaction says it all, though he later tweets that Instapaper has plenty of other features. Many fans will continue to use it, while casual iPhone users may never have used Instapaper anyway.

Twitter clients

As if Twitter's acquisition of TweetDeck and its warning to third-party developers to create something valuable wasn't enough, Apple's tight integration of Twitter functions into iOS 5 could spell the end for many downloadable Twitter apps. Unless they do something spectacular that draws power users to launch a separate app, most people will tweet directly from the many apps that will support it.

You'll still need a separate client to read Twitter, but the official app should do fine for that. Besides, what self-respecting egotistical iPhone owner wants to read what other people are doing? Other people are so boring.

Camera+

There are a huge number of photo applications for iOS and they've become more popular as Apple has improved its hardware.

Camera+ in particular has many of the functions Apple has now introduced free to iOS 5, including grid, digital zoom and photo retouching. That said, the £1.19 app includes additional features such as filters, which could still make it a good buy for those who want to do more with their pics.

The developer's initial reaction? "VOLUME BUTTON TO SNAP A PIC... WHAT AN AWESOME IDEA, APPLE! (eh, at least we're not @marcoarment right now)"

To-Do apps

Reminders will replace many simpler to-do apps such as Remember the Milk. We're surprised Apple hasn't included such a feature before now. More advanced scheduling and task-management apps will probably continue to be popular among those who need more extensive organisation.

Messaging apps

Apple's iMessage service may at first seem to spell disaster for third-party messengers, but it's worth bearing in mind that it only allows communication between iOS devices. You'll still need other apps to IM those on other platforms.

This isn't the first iOS upgrade to dump on some third-party apps. iOS 4's native Voice Memos meant most users didn't need to invest in other audio recording apps, for example. The social integration of iOS 5 will be a hard nut for some developers to crack. At least they have a few months to beef up their offerings, however, in the hope they'll still be attractive to users.

The moral of the story, for developers at least, is to make apps as useful and memorable as possible, build up a fan base and try to stay a few steps ahead of the mighty Apple. And possibly to split your eggs into a few other baskets -- Android, anyone?